Syringe Assembly with Plunger Having a Secondary Dispensing Reservoir

ABSTRACT

A syringe assembly is disclosed which includes a syringe body defining a first fluid reservoir and a fluid outlet. A plunger assembly includes a plunger rod and a plunger. The plunger is supported on a distal end of the plunger rod and defines a second fluid reservoir. The plunger is movable within the syringe body from a retracted position to an advanced position to eject fluid from the first fluid reservoir. A piercing member is supported on a distal end of the plunger rod within the second fluid reservoir. The piercing member is movable to pierce the plunger to eject fluid from the second fluid reservoir when a predetermined force is applied to the plunger in the advanced position.

This application claims priority from U.S. provisional application Ser.No. 61/076,841, filed Jun. 30, 2008, the entirety of which isincorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to syringes and, more particularly, to asyringe having a secondary reservoir for injecting a secondary solutionsubsequent to injection of the primary solution.

2. Background of Related Art

Intravenous or I.V. catheters which are inserted into a patient'svasculature, e.g., vein, to facilitate a variety of different medicalprocedures, including blood withdrawal, medication delivery, dialysis,etc., over an extended period of time are well known in the art. SuchI.V. catheters minimize the pain and discomfort to a patient associatedwith multiple needle injections which may be required during a hospitalstay.

Syringe assemblies are commonly used to inject fluids, e.g., medication,into an I.V. catheter. Typically, after a medication has been injectedfrom a syringe assembly into the I.V. catheter, a flush solution isinjected into the I.V. catheter to force any medication remaining in thecatheter into the patient.

One problem currently associated with the use of a syringe assembly toinject fluid into an I.V. catheter is that attachment of the syringeassembly to the I.V. catheter may introduce contaminants into the I.V.catheter or the reusable valve structure of the catheter, which may leadto infection in the patient.

It is known to inject an anti-microbial solution into an indwellingcatheter to guard against infection. However, the injection of ananti-microbial solution into I.V. catheter requires the attachment of asecond syringe to the I.V. catheter which further increases the risk ofinfection to the patient.

Accordingly, a continuing need exists in the medical arts for a syringeassembly which can function to flush an I.V. catheter assembly whileminimizing the risk of infection to a patient.

SUMMARY

A syringe assembly is disclosed which includes a syringe body defining afirst fluid reservoir and a fluid outlet. A plunger assembly includes aplunger rod and a plunger. The plunger is supported on a distal end ofthe plunger rod and defines a second fluid reservoir. The plunger ismovable within the syringe body from a retracted position to an advancedposition to eject fluid from the first fluid reservoir. A piercingmember is supported on a distal end of the plunger rod within the secondfluid reservoir. The piercing member is movable to pierce the plunger toeject fluid from the second fluid reservoir when a predetermined forceis applied to the plunger in the advanced position. In one embodiment,the plunger includes at least one external annular groove adjacent anoutwardly bowed internal wall and is collapsible upon application of thepredetermined force to the plunger. It is also envisioned that theplunger may be constructed of more than one material or component toprovide for axial stiffness but allow for collapsing or “folding” at thepredetermined force due to fluid pressure acting upon the internal wall.

The plunger can include a plurality of external annular grooves or havea bellows-like construction.

In one embodiment, the piercing member includes a piercing tip. Thepiercing member can include at least one external groove, wherein fluidin the second fluid reservoir flows along the at least one externalgroove to the fluid outlet. The at least one external groove can includea plurality of external grooves.

In one embodiment, the first fluid reservoir contains a first fluid andthe second fluid reservoir contains a second fluid which is differentfrom the first fluid. The first fluid can be a flush solution and thesecond fluid can be an anti-microbial solution.

In one embodiment, the plunger rod includes a circular disc secured tothe plunger and the circular disc includes a frangible portion. Thefrangible portion defines a centrally located secondary plunger which isdimensioned to move within the second fluid reservoir to eject fluidfrom the second fluid reservoir. The piercing member can extend distallyfrom a distal surface of the secondary plunger. The frangible portion isconstructed to break upon application of the predetermined force to theplunger. The predetermined force should be greater than the forcerequired to initiate movement of the plunger.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed syringe assembly with aplunger having a secondary dispensing reservoir are disclosed hereinwith reference to the drawings, wherein:

FIG. 1 is a side perspective view from the distal end of one embodimentof the presently disclosed syringe assembly with a plunger having asecondary dispensing reservoir;

FIG. 1A is a side cross-sectional view of the syringe assembly shown inFIG. 1 taken along section lines 1A-1A of FIG. 1 with the syringeplunger in a retracted position;

FIG. 2 is a side perspective exploded view from the distal end of thesyringe assembly shown in FIG. 1;

FIG. 3 is a side cross-sectional view of the syringe assembly shown inFIG. 1A with the syringe plunger in an advanced position;

FIG. 3A is an enlarged view of the indicated area of detail shown inFIG. 3;

FIG. 4 is a side cross-sectional view of the syringe assembly shown inFIG. 3 with the syringe plunger in an advanced and collapsed position;

FIG. 4A is an enlarged view of the indicated area of detail shown inFIG. 4;

FIG. 5 is a side cross-sectional view of another embodiment of thepresently disclosed syringe assembly with a plunger having a secondarydispensing reservoir and the plunger in a retracted position;

FIG. 5A is a side cross-sectional view of the syringe assembly shown inFIG. 5 with the plunger in an advanced position and the secondaryplunger partially advanced through the secondary reservoir;

FIG. 6 is a side cross-sectional view of an alternative embodiment ofthe presently disclosed syringe assembly plunger; and

FIG. 6A is a side cross-sectional view of yet another embodiment of thepresently disclosed syringe plunger.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed syringe assembly with a plungerhaving a secondary dispensing reservoir will now be described in detailwith reference to the drawings wherein like reference numerals designateidentical or corresponding elements in each of the several views. Inthis description, the term proximal is generally used to indicate therelative nearness of a referenced item to a user of the device and theterm distal is used to indicate the relative remoteness of a referenceditem to a user of the device.

FIGS. 1-3 illustrate one embodiment of the presently disclosed syringeassembly with a plunger having a secondary dispensing reservoir showngenerally as 10. Briefly, syringe assembly 10 includes a syringe body 12defining a primary fluid reservoir 14 and a plunger assembly 16. Syringebody 12 has a proximal open end 12 a having a gripping flange 18 and adistal end 12 b defining a conical or tapered fluid outlet 20. Aluer-type connector or similar connecting structure 22 is positionedabout fluid outlet 20. Connecting structure 22 is configured toreleasably engage connecting structure on a medical device (not shown),e.g., an indwelling catheter, to releasably secure syringe assembly 10to the medical device.

Plunger assembly 16 includes a plunger rod 24 and a plunger 26 (FIG.1A). The proximal end of plunger rod 24 includes a finger engagementmember 28 and the distal end of plunger rod 24 includes a circular disc30 (FIG. 2). Plunger rod 24 has a +-shaped body which interconnectsfinger engagement member 28 and circular disc 30. A stepped extension 32is formed on a distal face of disc 30. Extension 32 includes acylindrical body 34 and a step 36. As illustrated in FIG. 1A, step 36 isreceived within a stepped recess 38 formed within plunger 26 to secureplunger 26 onto the distal end of plunger rod 24. The distal face ofextension 32 has a longitudinal bore 40 (FIG. 2) which is dimensioned toreceive a piercing tip 42 which will be discussed in further detailbelow.

Referring to FIGS. 1A and 2, plunger 26 is formed of a resilientmaterial, e.g., rubber, and defines a secondary fluid reservoir 44 (FIG.1A). The outer surface of plunger 26 is dimensioned to sealingly engagean internal surface 46 of syringe body 12. An annular recess 48 isdefined about plunger 26. Annular recess 48 is provided to allow plunger26 to collapse after a predetermined axial force is applied to plunger26 as will be discussed in further detail below. The distal end ofplunger 26 includes a piercable area 50 of reduced thickness.

Plunger 26 also includes an internal wall 48 a which bows outwardly andis aligned with annular recess 48. Internal wall 48 a expands outwardlyas piercable tip 42 advances towards piercable area 50 of plunger 26 toincrease the width of secondary fluid reservoir 44 and compensate forthe reduced length of reservoir 44. It is noted that since fluids wouldnot be compressible within reservoir 44, the width of reservoir 44 mustincrease as plunger 26 is compressed to accommodate a fixed volume offluid.

Piercing tip 42 has a proximal end 52 (FIG. 2) which is fixedly securedwithin bore 40 of extension 32 of plunger rod 24 and a sharpened distalend 42 a. Alternatively, piercing tip 42 is formed integrally withextension 32. An external surface of piercing tip 42 defines one or morelongitudinal grooves 54 (FIG. 1A), e.g., four. Piercing tip 42 ispositioned within secondary fluid reservoir 44 of plunger 26 such thatdistal end 42 a of piercing tip 42 is positioned adjacent piercable area50 of plunger 26.

Referring to FIGS. 3 and 3A, when plunger assembly 16 is advanced from aretracted position (FIG. 1A) to an advanced position (FIG. 3), plunger26 forces fluid from primary reservoir 14 through fluid outlet 20 untilplunger 26 bottoms out on a distal wall 60 of syringe body 12. Whenplunger 26 bottoms out on distal wall 60, a further application of apredetermined force on plunger 26 transmitted through plunger rod 24causes internal wall 48 a of plunger 26 to bow outwardly such thatplunger 26 can collapse. It should be noted that the predetermined forcerequired to effect collapse of plunger 26 in combination with the forcerequired to pierce piercable area 50 of plunger 26 must be greater thanthe force required to initiate movement of plunger 26 and the forcerequired to eject fluid from primary reservoir 14.

Referring to FIGS. 4 and 4A, when the predetermined force required tocollapse plunger 26 is applied to plunger 26, plunger 26 collapsescausing sharpened distal end 42 a of piercing tip 40 to pierce piercablearea 50 of plunger 26. As plunger 26 collapses, fluid from withinsecondary fluid reservoir 44 is forced to flow through grooves 54 ofpiercing tip 42 and through fluid outlet 20. As this occurs, the distalface 32 a of extension 32 of plunger rod 24 functions as a secondaryplunger to eject fluid from secondary fluid reservoir 44. It is notedthat a vent (not shown) may be provided through or around a proximal endof plunger 26 to vent annular recess 46 as plunger 26 collapses.

Syringe assembly 10 is suitable for use with an indwelling catheterassembly (not shown). More specifically, in one presently disclosedmethod of use, syringe assembly 10 is provided with a flush or locksolution, e.g., saline, in primary reservoir 14 and an anti-microbialsolution, e.g., Poly(hexamethylenebiguanide) (PHMB), in the secondaryfluid reservoir 44. Syringe assembly 10 is secured to an indwellingcatheter assembly (not shown) to flush the catheter assembly. After theflush/lock solution has been injected into the catheter assembly fromthe primary reservoir 14, the anti-microbial solution is injected intothe catheter assembly. In one embodiment, the anti-microbial solutionhas a viscosity which is greater than that of the flush/lock solutionsuch that the anti-microbial solution will tend to reside withinreusable valve structure of the indwelling catheter (not shown). Theinjection of an anti-microbial solution into the reusable valvestructure of an indwelling catheter minimizes the risk of patientinfection caused by sources originating from the valve structure of theindwelling catheter. The presently disclosed syringe assemblyfacilitates the sequential injection of a flush/lock solution andanti-microbial solution into an indwelling catheter using a singlesyringe to further minimize the risk of infection to the patient.

In an alternative method of use, the primary reservoir may store a firstfluid which mixes with a second fluid stored in the secondary fluidreservoir to provide enhanced anti-microbial activity in the reusablevalve structure of an indwelling catheter. For example, the primaryreservoir may store EDTA and the secondary fluid reservoir may storehydrogen peroxide. When the EDTA mixes with the hydrogen peroxide withinthe valve structure of the indwelling catheter, enhanced anti-microbialactivity is effected.

It is also contemplated that the reusable valve structure of theindwelling catheter may be coated or impregnated with silver or silverparticles and the secondary fluid reservoir may include a fluid, e.g.,EDTA, which interacts with the silver or silver particles to enhanceanti-microbial activity within the reusable valve structure of theindwelling catheter.

FIGS. 5 and 5A illustrate another embodiment of the presently disclosedsyringe assembly shown as 100. Syringe assembly 100 includes a syringebody 112 defining a primary fluid reservoir 114 and a plunger assembly116. Syringe body 112 has a proximal open end 112 a and a distal end 112b defining a tapered fluid outlet 120. A luer-type connector 122 or thelike is positioned about fluid outlet 120.

Plunger assembly 116 includes a plunger rod 124 and a plunger 126.Plunger rod 124 includes a circular disc 128 which is secured to aproximal surface of plunger 126 such as by adhesives. Circular disc 128includes a circular frangible portion 130 which defines an innersecondary plunger 132 on circular disc 128. A piercing tip 142 issecured to or formed integrally with secondary plunger 132. Piercing tip142 extends distally from secondary plunger 132 and has a tip 142 awhich is positioned adjacent a piercable portion 150 of plunger 126.Piercing tip 142 defines one or more grooves 154 which will be discussedin further detail below.

Plunger 126 defines a secondary fluid reservoir 144 and includes anouter surface which sealingly engages an inner wall 160 of syringe body112 at its proximal and distal ends. A central portion of plunger 26includes a concavity 148 a defining a thinned side wall portion 148 b ofplunger 126. The proximal end of reservoir 144 is sealed by secondaryplunger 132. When plunger assembly 116 is advanced from a retractedposition (FIG. 5) to an advanced position such that a distal face 126 aof plunger 126 engages a distal wall 162 of syringe body 112, furtherapplication of a predetermined force on plunger assembly 116 causesfrangible portion 130 to break. When frangible portion 130 breaks,secondary plunger 132 separates from the remaining portion of circulardisc 128 and begins to move through secondary fluid reservoir 144.During initial advancement of secondary plunger 132, thinned side wallportion 148 b bows outwardly to compensate for the reduction in lengthof secondary fluid reservoir 144 and accommodate the fixed volume offluid stored within reservoir 144. When piercing tip 142 pierces plunger126, fluid is ejected from reservoir 144 through fluid outlet 120. Asdiscussed above with respect to syringe assembly 10, the predeterminedforce required to effect separation of secondary plunger 132 fromcircular disc 128 must be greater than the force required to initiatemovement of plunger assembly 16. It is noted that a portion of the outerperiphery of secondary plunger 132 can be provided with a sealingelement, e.g., an O-ring, to enhance sealing engagement of secondaryplunger 132 within inner wall defining reservoir 144. It is also notedthat a vent (not shown) can be provided through or around a proximal endof plunger 126 to facilitate outward movement of thinned side wallportion 148 b.

FIGS. 6 and 6A illustrate alternative embodiments of plunger 26. In FIG.6, plunger 226 defines a pair of annular recesses 248, as compared to asingle annular recess 48 defined in plunger 26 (FIG. 1A). In FIG. 6A,plunger 336 defines an intermediate bellows type configuration 338. Eachof the plunger configurations shown in FIGS. 6 and 6A providealternative structure for facilitating collapse of plunger. It isenvisioned that a variety of different configurations could be used toachieve this result. It is further envisioned that the plunger need notcollapse but rather may include other structure, such as that shown inFIGS. 5 and 5A, to dispense fluid from the secondary reservoir.

It will be understood that various modifications may be made to theembodiments disclosed herein. For example, it is envisioned that theplunger may be constructed of more than one material or component toallow for axial stiffness but also allow for collapsing or folding uponapplication of a predetermined force. Therefore, the above descriptionshould not be construed as limiting, but merely as exemplifications ofpreferred embodiments. Those skilled in the art will envision othermodifications within the scope and spirit of the claims appended hereto.

1. A syringe assembly comprising: a syringe body defining a first fluidreservoir and a fluid outlet; a plunger assembly including a plunger rodand a plunger, the plunger being supported on a distal end of theplunger rod and defining a second fluid reservoir, the plunger beingmovable within the syringe body from a retracted position to an advancedposition to eject fluid from the first fluid reservoir; and a piercingmember supported on a distal end of the plunger rod within the secondfluid reservoir, the piercing member being movable to pierce the plungerto eject fluid from the second fluid reservoir when a predeterminedforce is applied to the plunger in the advanced position of the plunger.2. The syringe assembly according to claim 1, wherein the plungerincludes at least one external annular groove and is collapsible uponapplication of the predetermined force.
 3. The syringe assemblyaccording to claim 2, wherein the plunger includes a plurality ofexternal annular grooves.
 4. The syringe assembly according to claim 2,wherein the plunger has a bellows-like construction.
 5. The syringeassembly according to claim 2, wherein the piercing member includes apiercing tip.
 6. The syringe assembly according to claim 5, wherein thepiercing member includes at least one external groove and fluid in thesecond fluid reservoir flows along the at least one external groove tothe fluid outlet.
 7. The syringe assembly according to claim 6, whereinthe at least one external groove includes a plurality of externalgrooves.
 8. The syringe assembly according to claim 1, wherein the firstfluid reservoir contains a first fluid and the second fluid reservoircontains a second fluid which is different from the first fluid.
 9. Thesyringe assembly according to claim 8, wherein the first fluid is aflush solution and the second fluid is an anti-microbial solution. 10.The syringe assembly according to claim 1, wherein the plunger rodincludes a circular disc secured to the plunger.
 11. The syringeassembly according to claim 10, wherein the circular disc includes afrangible portion, the frangible portion defining a central secondaryplunger, the secondary plunger being dimensioned to move within thesecond fluid reservoir to eject fluid from the second fluid reservoir.12. The syringe assembly according to claim 11, wherein the piercingmember extends distally from a distal surface of the secondary plunger.13. The syringe assembly according to claim 11, wherein the frangibleportion is constructed to break upon application of the predeterminedforce to the plunger.
 14. The syringe assembly according to claim 1,wherein the predetermined force is greater than the force required toinitiate movement of the plunger.